Dispatch communication systems are known to include a wireless infrastructure and a plurality of communication units, such as two-way radios. Some dispatch systems, such as those used for public safety, also include a dispatch console and a so-called "computer aided dispatch (CAD) system" that includes a display-based terminal to control communications between the communication units. The CAD terminal typically displays categorized tables of information to the terminal user (typically referred to as a "dispatcher" or "dispatch operator"). For example, the CAD terminal may display queues of currently pending incidents and/or a list of communication units that are currently available. In addition, some CAD terminals include an integrated mapping program that enables the CAD terminal to display locations of communication units on a map that represents a geographic area supported by the dispatch system. The locations of the communication units are typically provided to the CAD system on a periodic basis by an automatic vehicle location (AVL) system that is coupled to the CAD system via a dedicated communication link.
In addition to receiving communication unit location information, the CAD system may also receive incident information from a 911 system that is coupled to the CAD system. In such a case, the map displays the origination point of a 911 telephone call to the dispatcher as an icon on the map. By viewing communication unit location, communication unit status, and incident location on the map, the dispatcher can quickly determine which communication unit users (e.g., policemen, firemen, paramedics, and so forth) would be in the best situation to respond to the incident. As an incident is attended to by users of the communication units, the status of the communication units associated with such users is updated either manually by the dispatcher or automatically by the CAD system responsive to messaging from the wireless infrastructure. In the latter case, the wireless infrastructure receives status updates over a wireless communication channel from the communication units that are participating in the handling of the incident. Changes in communication unit status are typically indicated to the dispatcher by some type of visual change, such as a color change or icon update, to the participating unit's representation on the map.
A map display, with icons representing the incidents and the communication units with their current status, gives a dispatcher a powerful tool for quickly evaluating an emergency situation. By using standard graphical user interface (GUI) cursor interaction (e.g., "point and click" or "drag and drop"), the dispatcher can manipulate the screen icons to assign units to incidents. In some systems, the action of assigning communication units to incidents on the map automatically sends data to the assigned communication units (e.g., if the units are equipped with mobile data terminals) to enable the communication unit users to immediately obtain critical information related to the incident, such as the incident location and other details.
In many situations, the communication units assigned to handle an incident belong to different agencies, such as police, fire, ambulance, public works, and so forth. The communication units are, however, generally programmed to permit direct group communications only with other communication units from the same agency, and are not programmed to facilitate direct group communications between communication units of different agencies. To permit such inter-agency communications, dispatch systems generally provide for dynamic regrouping of communication units into a common talkgroup, thereby enabling direct group communications between regrouped units. Dynamic regrouping is typically performed by a radio management program in the dispatch console or by a CAD program that interacts with the dispatch console via a defined interface, such as an application programming interface.
In the case of a large emergency incident, many communication units may arrive at and leave the scene of the emergency during the course of the emergency. Therefore, grouping and ungrouping of the units attending to the emergency is very important to enable the attending units to directly communicate while at the scene, but enable the units to communicate in their original talkgroups (e.g., with other units of their particular agency) after leaving the scene. In existing dispatch systems, the dispatcher or another individual, such as an emergency response supervisor, must manually group and ungroup units as they arrive at and leave the scene of the emergency incident using the aforementioned radio management or CAD program. The CAD or radio management dynamic grouping program can be run from or displayed on the CAD terminal; however, such programs require the dispatcher to leave the map environment to execute them, thereby losing the benefit of having a map display to view the system and, in particular, the geographic area near the emergency incident in the first place.
Therefore, a need exists for a method and apparatus that allows a user of a display-based terminal, such as a CAD terminal, having an integrated mapping program to dynamically group and ungroup communication units from a single map environment.